Description

A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data (e.g. using /dev/urandom on Linux) or to leak Windows credentials via SMB links when the email is viewed in HTML mode. While user interaction is required to download the .pdf file, visual obfuscation can conceal the download trigger. Viewing the email in HTML mode is enough to load external content. This vulnerability was fixed in Thunderbird 128.11.1 and Thunderbird 139.0.2.

INFO

Published Date :

2025-06-11T12:07:50.430Z

Last Modified :

2026-04-13T14:28:34.275Z

Source :

mozilla
AFFECTED PRODUCTS

The following products are affected by CVE-2025-5986 vulnerability.

Vendors Products
Mozilla
  • Thunderbird
Redhat
  • Enterprise Linux
  • Rhel Aus
  • Rhel E4s
  • Rhel Eus
  • Rhel Tus
REFERENCES

Here, you will find a curated list of external links that provide in-depth information to CVE-2025-5986.

URL Resource
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1958580%2C1968012 cve-icon cve-icon
https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-5986 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-5986 cve-icon
https://www.mozilla.org/security/advisories/mfsa2025-49/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2025-50/ cve-icon cve-icon
Login to claim this CVE

CVSS Vulnerability Scoring System

Detailed values of each vector for above chart.
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact